The Toyota Prius has had ESC (Electronic Stability Control) in models since August 2003.  The first time this was included was in the model change to the NHW20  chassis, while only in the G model, not the S.

This also has the triple digit emissions code, so it is still importable into New Zealand with the strict triple digit AND ESC restrictions.  In Toyota language they call it “Vector Stability Control”.

So when searching for a Prius with the electronic stability controls system, you need to search for models that came out after the model change in September 2003, or the “20” series or the chassis NHW20.  Finally you need to focus on the model type, as not all the models had stability control.  You need to focus on the “G” series.  Here is a photo of the stats from a 2004 Toyota catalog: